1. Fully Assembled Device: Mmdvm Hotspot Is A Fully Assembled Device That Supports Dmr, Ysf, P25, D-Star And System Fusion. With Orange Pi, It Supports Duplex Mode And Simplex Mode. 2. Radio Frequency: In Duplex Mode, Support Uhf 430-440mhz; In Simple Mode, Support Uhf 430-440mhz And Vhf 140-150mhz. Tx=0,Rx=0 Is The Best Adjustment, No Offset Is Required. 3. Easy Installation: The Software Pi-Star Is Pre-Installed On The Tf Card, No Need To Download It Again. Note: When You Flash The Tf Card With A Version Of Software, Please Do Not Copy Directly To The Tf Card. Use A Writing Tool To Write The Software On The Tf Card. 4. Usb Cable Expansion Interface: If You Want To Use A Usb Cable To Connect The Duplex Mmdvm To The Computer, You Must Use The Usb Cable For The Expansion Interface Included In The Package. The Universal Android Cable Connector Is Relatively Short And The Connection Doesn'T Work. 5. Duplex Hotspot Board, Multi-Mode Digital Voice Modem Type: for Raspberry Pi 4th Generation Size: About 1.3x2.2x2.2cm Colour:black Material:Metal Package Contents: 1 x MMDVM Hotspot Board 1 x 8gb Memory Card 2 x Antenna 1 x Usb Cable 1 x English Instruction Manual Note:Different Batches May Have Differences In Product Appearance, Color, And Printed Characters, Which Will Not Affect The Use